What's my options?iMac i7 won't boot after El Capitan install

fix

work around

i have a 2011 27inch iMac i7 after the install boot of El Capitan my iMac will not boot. I get the grey screen with the apple and the progress bar but the progress bar does't move. I reinstalled from recovery disk and after initial boot after install the same thing - grey screen with the apple and the progress bar but the progress bar does't move/

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